package api

import (
	"encoding/json"
	"net/http"

	"github.com/go-chi/chi/v5"
	"github.com/local-mcp/local-mcp-go/internal/events"
	"github.com/local-mcp/local-mcp-go/internal/store"
)

func handleListInstructions(stores Stores) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		status := r.URL.Query().Get("status")
		if status == "" {
			status = "all"
		}
		items, err := stores.Instructions.List(status)
		if err != nil {
			writeError(w, http.StatusInternalServerError, err.Error())
			return
		}
		writeJSON(w, http.StatusOK, map[string]any{"items": items})
	}
}

func handleCreateInstruction(stores Stores, broker *events.Broker) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var body struct {
			Content string `json:"content"`
		}
		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
			writeError(w, http.StatusBadRequest, "Invalid JSON")
			return
		}
		if body.Content == "" {
			writeError(w, http.StatusBadRequest, "content is required")
			return
		}

		item, err := stores.Instructions.Create(body.Content)
		if err != nil {
			writeError(w, http.StatusInternalServerError, err.Error())
			return
		}

		counts, _ := stores.Instructions.Counts()
		broker.Broadcast("instruction.created", map[string]any{"item": item})
		broker.Broadcast("status.changed", map[string]any{"queue": counts})

		writeJSON(w, http.StatusCreated, item)
	}
}

func handleUpdateInstruction(stores Stores, broker *events.Broker) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		id := chi.URLParam(r, "id")
		var body struct {
			Content string `json:"content"`
		}
		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
			writeError(w, http.StatusBadRequest, "Invalid JSON")
			return
		}

		item, err := stores.Instructions.Update(id, body.Content)
		if err == store.ErrNotFound {
			writeError(w, http.StatusNotFound, "Instruction not found")
			return
		}
		if err == store.ErrAlreadyConsumed {
			writeError(w, http.StatusConflict, "Cannot edit consumed instruction")
			return
		}
		if err != nil {
			writeError(w, http.StatusInternalServerError, err.Error())
			return
		}

		broker.Broadcast("instruction.updated", map[string]any{"item": item})
		writeJSON(w, http.StatusOK, item)
	}
}

func handleDeleteInstruction(stores Stores, broker *events.Broker) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		id := chi.URLParam(r, "id")
		if err := stores.Instructions.Delete(id); err == store.ErrNotFound {
			writeError(w, http.StatusNotFound, "Instruction not found")
			return
		} else if err == store.ErrAlreadyConsumed {
			writeError(w, http.StatusConflict, "Cannot delete consumed instruction")
			return
		} else if err != nil {
			writeError(w, http.StatusInternalServerError, err.Error())
			return
		}

		counts, _ := stores.Instructions.Counts()
		broker.Broadcast("instruction.deleted", map[string]any{"id": id})
		broker.Broadcast("status.changed", map[string]any{"queue": counts})

		w.WriteHeader(http.StatusNoContent)
	}
}

func handleClearConsumed(stores Stores, broker *events.Broker) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		items, err := stores.Instructions.List("consumed")
		if err != nil {
			writeError(w, http.StatusInternalServerError, err.Error())
			return
		}

		if err := stores.Instructions.DeleteConsumed(); err != nil {
			writeError(w, http.StatusInternalServerError, err.Error())
			return
		}
		counts, _ := stores.Instructions.Counts()
		cleared := len(items)
		broker.Broadcast("history.cleared", map[string]any{"count": cleared})
		broker.Broadcast("status.changed", map[string]any{"queue": counts})
		writeJSON(w, http.StatusOK, map[string]any{"cleared": cleared})
	}
}